Riparian Fringe Research Articles

A Contribution to Trees and Shrubs Checklist in Kuala Keniam at Taman Negara, Pahang, Malaysia

Abstract The forested area around Kuala Keniam is a part of Taman Negara (Pahang) and is categorized as a primary lowland dipterocarp, riparian fringe and limestone forests. A study of flora that focuses on the trees and shrubs was conducted during the scientific expedition in September 2020, organised by Universiti Teknologi MARA (UiTM). The results identified as many as 187 taxa of trees and shrubs consisting of 124 genera and 49 plant families from the lowland dipterocarp forest. A total of nine endemic taxa to Peninsular Malaysia were also recorded namely Aporosa globifera, Baccaurea pyriformis, Cinnamomum mollissimum, Enicosanthum fuscum, Lithocarpus curtisii, Mallotus griffithianus, M. penangensis, Ryparosa fasciculata and Schoutenia kunstleri. Another three taxa viz. Elaeocarpus obtusatus ssp. apiculatus, Popowia tomentosa and Sterculia rubiginosa var. setistipula were considered as the new additional record for Pahang state. It is hoped that the information from this study can be used as references to help other researchers as well as stakeholders in ecotourism management and forest conservation plan.

Soil microbes of an urban remnant riparian zone have greater potential for N removal than a degraded riparian zone.

Soils in the riparian zone, the interface between terrestrial and aquatic ecosystems, may decrease anthropogenic nitrogen (N) loads to streams through microbial transformations (e.g., denitrification). However, the ecological functioning of riparian zones is often compromised due to degraded conditions (e.g., vegetation clearing). Here we compare the efficacy of an urban remnant and a cleared riparian zone for supporting a putative denitrifying microbial community using 16S rRNA sequencing and quantitative polymerase chain reaction of archaeal and bacterial nitrogen cycling genes. Although we had no direct measure of denitrification rates, we found clear patterns in the microbial communities between the sites. Greater abundance of N-cycling genes was predicted by greater soil ammonium (N-NH4 ), organic phosphorus, and C:N. At the remnant site, we found positive correlations between microbial community composition, which was dominated by putative N oxidisers (Nitrosomonadaceae, Nitrospiraceae and Nitrosotaleaceae), and abundance of ammonia-oxidizing archaea (AOA), nirS, nirK and nosZ, whereas the cleared site had lower abundance of N-oxidisers and N cycling genes. These results were especially profound for the remnant riparian fringe, which suggests that this region maintains suitable soil conditions (via diverse vegetation structure and periodic saturation) to support putative N cyclers, which could amount to higher potential for N removal.

Anammox and denitrification separately dominate microbial N-loss in water saturated and unsaturated soils horizons of riparian zones

Fertilized agroecosystems may show considerable leaching of the mobile nitrogen (N) compound NO3−, which pollutes groundwater and causes eutrophication of downstream waterbodies. Riparian buffer zones, positioned between terrestrial and aquatic environments, effectively remove NO3− and serve as a hotspot for N2O emissions. However, microbial processes governing NO3− reduction in riparian zones still remain largely unclear. This study explored the underlying mechanisms of various N-loss processes in riparian soil horizons using isotopic tracing techniques, molecular assays, and high-throughput sequencing. Both anaerobic ammonium oxidation (anammox) and denitrification activity were maximized in the riparian fringe rather than in the central zones. Denitrifying anaerobic methane oxidation (damo) process was not detected. Interestingly, both contrasting microbial habitats were separated by a groundwater table, which forms an important biogeochemical interface. Denitrification dominated cumulative N-losses in the upper unsaturated soil, while anammox dominated the lower oxic saturated soil horizons. Archaeal and bacterial ammonium oxidation that couple dissimilatory nitrate reduction to ammonium (DNRA) with a high cell-specific rate promoted anammox even further in oxic subsurface horizons. High-throughput sequencing and network analysis showed that the anammox rate positively correlated with Candidatus ‘Kuenenia’ (4%), rather than with the dominant Candidatus ‘Brocadia’. The contribution to N-loss via anammox increased significantly with the water level, which was accompanied by a significant reduction of N2O emission (∼39.3 ± 10.6%) since N-loss by anammox does not cause N2O emissions. Hence, water table management in riparian ecotones can be optimized to reduce NO3− pollution by shifting from denitrification to the environmentally friendly anammox pathway to mitigate greenhouse gas emissions.

Water vapor absorption allows for volume expansion during molting in Armadillidiumvulgare and Porcelliodilatatus (Crustacea, Isopoda, Oniscidea).

Arthropods require periodic molting in order to grow which presents a number of challenges to terrestrial taxa. Following ecdysis, the pliant new cuticle is susceptible to buckling under gravity and requires elevated hydrostatic pressure for support. Terrestrial species also require a mechanism of volume expansion and stretching of the integument prior to sclerotization, a need that is readily met in aquatic arthropods by drinking. Options for land arthropods include drinking of dew, swallowing of air, or using muscular contractions to inflate air sacs in tracheate taxa. In this study we tested the hypothesis that crinochete terrestrial isopods (Isopoda: Oniscidea: Crinocheta) exploit their capacity for active water vapor absorption (WVA) to increase volume during molting. Two crinochete species, Armadillidiumvulgare and Porcelliodilatatus, were studied and compared with the non-absorbing species Ligidiumlapetum (Oniscidea: Ligiamorpha). Pre-molting animals were identified by sternal CaCO3 deposits and exposed to 100% or 97% relative humidity (RH). Mass-changes were monitored by daily weighing and the timing of the posterior and anterior ecdyses was used to categorize time (days premolt and days post-molt) over the molt cycle. In each treatment RH, A.vulgare and P.dilatatus showed a progressive mass increase from 5 days premolt until the posterior or anterior ecdysis, followed abruptly by period of mass-loss lasting 3–4 days post-molt. The fact that the initial mass-gain is seen in 97 % RH, a humidity below the water activity of the hemolymph, confirms the role of WVA. Similarly, since the post-molt mass-loss is seen in 100 % RH, this must be due to active expulsion of water, possibly via maxillary urine. Concurrent changes in hemolymph osmolality were monitored in a separate batch of A.vulgare and show sustained osmolality during premolt and an abrupt decrease between the anterior and posterior ecdysis. These patterns indicate a mobilization of sequestered electrolytes during premolt, and a loss of electrolytes during the post-molt mass-loss, amounting to approximately 8.6 % of total hemolymph solutes. WVA, in conjunction with pulses of elevated hemolymph pressure, provides an efficient mechanism of pre-molt volume expansion prior to and during the biphasic molt in these species. Premolt Ligidiumlapetum exposed to same treatments failed to molt successfully and no premolt animals survived to day 3 (72 h) even in 100 % RH. The apparent dependence of this species on liquid water for successful molting could explain its obligatory association with riparian fringe habitats.

Vegetation community response to hydrologic and geomorphic changes following dam removal

AbstractDam removal can restore fish passage, natural flow regimes, sediment transport in streams, dispersal of organic matter, and drift of aquatic insects. However, dam removal also impacts the riparian vegetation, with both immediate and delayed responses. In this study, we measure vegetation change at the Merrimack Village Dam site on the Souhegan River in Merrimack, NH, USA. The August 2008 removal caused a ~3‐m drop in water level and rapid erosion of impounded sediment, with ~50% removed in the first 3 months. Terrace, floodplain, and wetland communities were surveyed in summer 2007, 2009, 2014, and 2015. Temporal change was quantified using Analysis of Similarity on the Bray–Curtis dissimilarity matrix. Only herbaceous vegetation closest to the river channel and in the off‐channel wetland changed significantly. The herbaceous plots directly adjacent to the impoundment eroded to bare sand in 2009, but by 2014, the original riparian fringe community had re‐established in the newly developed floodplain. Between 2007 and 2014, the off‐channel wetland area changed from aquatic species to a stable terrestrial community that persisted without significant change in 2015. The vegetation response was greatest in areas with the largest geomorphic and hydrologic change. These included the channel margin where erosion and bank slumping created an unstable scarp. The mid‐channel island and off‐channel wetland were strongly affected by the lowered water table. However, large unvegetated areas never persisted nor did the areal coverage of invasive species expand, which are two frequent concerns of dam removal stakeholders.

Disproportionate Contribution of Riparian Inputs to Organic Carbon Pools in Freshwater Systems.

A lack of appropriate proxies has traditionally hampered our ability to distinguish riverine organic carbon (OC) sources at the landscape scale. However, the dissection of C4 grasslands by C3-enriched riparian vegetation, and the distinct carbon stable isotope signature (δ13C) of these two photosynthetic pathways, provides a unique setting to assess the relative contribution of riparian and more distant sources to riverine C pools. Here, we compared δ13C signatures of bulk sub-basin vegetation (δ13CVEG) with those of riverine OC pools for a wide range of sites within two contrasting river basins in Madagascar. Although C3-derived carbon dominated in the eastern Rianala catchment, consistent with the dominant vegetation, we found that in the C4-dominated Betsiboka basin, riverine OC is disproportionately sourced from the C3-enriched riparian fringe, irrespective of climatic season, even though δ13CVEG estimates suggest as much as 96% of vegetation cover in some Betsiboka sub-basins may be accounted for by C4 biomass. For example, δ13C values for river bed OC were on average 6.9 ± 2.7‰ depleted in 13C compared to paired estimates of δ13CVEG. The disconnection of the wider C4-dominated basin is considered the primary driver of the under-representation of C4-derived C within riverine OC pools in the Betsiboka basin, although combustion of grassland biomass by fire is likely a subsidiary constraint on the quantity of terrestrial organic matter available for export to these streams and rivers. Our findings carry implications for the use of sedimentary δ13C signatures as proxies for past forest-grassland distribution and climate, as the C4 component may be considerably underestimated due to its disconnection from riverine OC pools.Electronic supplementary materialThe online version of this article (doi:10.1007/s10021-014-9772-6) contains supplementary material, which is available to authorized users.

Seasonal Selection Preferences for Woody Plants by Breeding Herds of African Elephants (Loxodonta africana) in a Woodland Savanna

To evaluate dynamics of elephant herbivory, we assessed seasonal preferences for woody plants by African elephant breeding herds in the southeastern part of Kruger National Park (KNP) between 2002 and 2005. Breeding herds had access to a variety of woody plants, and, of the 98 woody plant species that were recorded in the elephant's feeding areas, 63 species were utilized by observed animals. Data were recorded at 948 circular feeding sites (radius 5 m) during wet and dry seasons. Seasonal preference was measured by comparing selection of woody species in proportion to their estimated availability and then ranked according to the Manly alpha (α) index of preference. Animals demonstrated a selection preference in feeding on woody vegetation, andGrewia hexamita, Grewia bicolor, Grewia flavescens, andGrewia monticolawere selected consistently more over all seasons. In addition, our results indicate that elephant herds have a low preference for at least some of the woody species prone to extirpation and that feeding preferences for woody plants do not account for the association of elephants and riparian fringe habitat.

Tertiary palynomorph assemblage from eastern Chenor, Pahang

A palynological study has been carried out on samples from a well exposed outcrop near Kg. Pejing along the road connecting Chenor and Paloh Hinai in the central part of Pahang. This well exposed outcrop is described as flat interbedded carbonaceous mudstone and sandstone. A palynological investigation of the outcrop section has revealed that the palynomorph assemblages were dominated by typical Tertiary palynomorphs such as Lanagiopollis emarginatus, Discoidites borneensis, Taxodiaceae, Stenochlaena palustris, Asplenium type, freshwater, peat swamp pollen and abundant tricolpate and tricolporate pollen. These palynomorph assemblages suggest the occurrence of ephemeral peat swamp and riparian fringe type environment. The age of the rock succession is probably Late Miocene and/or younger based on the presence of certain stratigraphically significant and age restricted taxa such as Lanagiopollis emarginatus and Stenochlaenidites papuanus.

Transport of Agricultural Pb, As and P through a Riparian Wetland

A 100-y geochemical record preserved in the sediments of a Mississippi oxbow lake yields evidence that chemicals entering from agricultural fields are only temporarily sequestered in the riparian fringe prior to active removal and transport to open water. Elevated concentrations of Pb and As, corresponding to peak historical use of lead arsenate pesticide, are clearly identified in open water sediment cores, but are absent in cores from the riparian fringe; P concentrations are also significantly higher in the open water cores than in the riparian fringe. A conceptual model is proposed where elements initially deposited in the riparian zone are seasonally remobilized by release from decomposing litter, and through uptake by wetland trees that return elements to the litter through leaf senescence. Within the riparian zone, seasonal remobilization eventually diffuses or eliminates the historical record. Elements that reach and settle out in the open water environment are sequestered and an historical geochemical record is preserved.

An assessment of the use of remote sensing to map habitat features important to sustaining lamprey populations

Abstract This study describes the use of colour aerial photography and Airborne Thematic Mapper (ATM) multispectral imagery (420–1050 nm) to map gravel‐bed river habitats important to sustaining river lamprey (Lampetra fluviatilis) — an aquatic species with high conservation interest in Europe. The accuracy of the remote sensing approach was assessed by comparing the output from automated mapping of physical habitat features using image analysis and GIS and habitat maps derived from field survey. Unsupervised classification of the aerial photography and ATM imagery mapped hydraulic habitat such as pools and riffles with overall accuracies of 57% and 65.5% respectively. Submerged sand and silt deposits, which are important to river lamprey ammocoetes could not be identified on the imagery by simple unsupervised or supervised classification. They could be mapped indirectly, however, by association between their presence and morphological attributes such as backwaters and embayments in the bank profile detectable on the imagery. Remotely determining the likely presence and location of lamprey ammocoete habitat can be useful in planning detailed electrofishing campaigns to estimate lamprey densities, to assess conservation status and any change over time, and to determine the need for restoration strategies. The results suggest that on rivers wider than 20 m without a continuous wooded riparian fringe, and where there is good quality imagery, it is possible to automate mapping of physical habitat features important to many river species with high nature conservation interest. As a result organizations charged with monitoring and conserving river species should consider investing in airborne imagery covering river systems of high conservation value. Copyright © 2007 John Wiley & Sons, Ltd.

English

A pond rehabilitation and environmental educational project were proposed by Cliffs Michigan Mining Company (CMMC) and approved by the Michigan Department of Environmental Quality (MDEQ) and the United States Environmental Protection Agency (USEPA) as partial fulfillment of conditions for a stream mitigation permit. The goals of the project were the rehabilitation of a pond on a tributary of a local trout stream, enhancement of public access and appreciation, and the initiation of a site-based environmental education curriculum dealing with aquatic and riparian ecosystems. CMMC undertook a suite of actions to rehabilitate the fresh water pond created by an underground mining operation in 1912 and make accessible to local schools the aquatic and riparian ecosystems of the pond. The rehabilitated pond and riparian zone also provides an accessible natural area available to citizens of the nearby town for such activities as hiking, biking, walking, fishing and nature study. The project was a partnership with the local governmental unit and local school districts. Vegetative enhancement included the planting of native shrubs and wildflowers along with showy herbaceous plants in the pond, on the riparian fringe and the surrounding area. A signed interpretive trail was designed and developed around the pond. Local schools built and installed picnic tables, benches and a kiosk. CMMC developed pond lesson plans and a teaching kit tied to the Michigan Curriculum Framework and hosted a workshop for teachers from nine local schools. Classes regularly utilize the pond during the school year by conducting environmental studies. Nesting boxes, wildflower gardens, bat houses, frog deformity surveys and water quality studies are a few of the activities that have been conducted at the pond. Additional

Fuelwood availability and use in the Richtersveld National Park, South Africa

Concern has been voiced about the possible over-use of fuelwood from the riparian fringe by pastoralist herders in the Richtersveld National Park (RNP). This coincided with the current examination and modelling of the supply and use of ecosystem goods and services in the Gariep Basin as part of the Southern African Millennium Assessment (SAfMA). This paper reports on a study to index the current availability of deadwood within the riparian zone of RNP, its relationship with proximity to human habitation, and species preferences of the local herders. Deadwood availability was assessed per woody species and on the ground in 12 transects within the riparian fringe. Herders were interviewed regarding their species preferences, and the composition of woodpiles was examined. There was no relationship between the percentage of attached deadwood on the tree, or the percentage deadwood ground cover, and the distance from herder stockposts. Euclea pseudobenus and Tamarix usneoides were the dominant species in the riparian fringe. There was strong selection for Ziziphus mucronata as a fuelwood species and only marginal or random selection for E. pseudobenus. Tamarix usneoides and Prosopis sp. were abundant in the riparian zone, but were not used for fuelwood. There was a significant difference between species with respect to the mean proportion of the stem that was dead, the highest being Z. mucronata (± 28 % deadwood), followed by T. usneoides (± 12 %). Most of the Prosopis trees had no deadwood. Across all species, the mean percentage dead per tree was approximately 15 %. Additionally, detached deadwood covered just less than 9 % of ground area, averaged across all plots and transects. All the variables measured indicated that there seems to be little need for concern over the current fuelwood extraction activities of pastoralists within the RNP. There was no clear evidence of cutting of branches or deadwood. The abundance of both attached and detached deadwood was not depleted close to human habitation. There was still abundant deadwood, even on preferred species. The most preferred species (Ziziphus mucronata) had the greatest mean proportion of deadwood. The herders stated that they only used deadwood, and that there was plenty. They rarely used driftwood washed down the river, although there was an abundance of it. Thus, overall, there was no sign of depletion of the deadwood resource, even on favoured species, or degradation of the productive capacity for deadwood.